Buletinul Ştiinţific al Universităţii “Politehnica” din Timisoara, ROMÂNIA Seria CHIMIE ŞI INGINERIA MEDIULUI Chem. Bull. "POLITEHNICA" Univ. (Timişoara) Volume 53(67), 1-2, 2008 244 Simulation of NO 2 Emission Dispersion in Timisoara City, in a Certain Reference Point in Relation with a Stationary Source H. Pirlea * , G.A. Brusturean * , D. Silaghi-Perju ** , D. Perju * * POLITEHNICA University of Timisoara, Industrial Chemistry and Environmental Engineering Faculty, Timisoara, Victoriei Square, nr. 2, Romania ** POLITEHNICA University of Timisoara, Mechanical Engineering Faculty, Blv.Mihai Viteazu 1, RO-300222 TIMISOARA, ROMANIA, Tel. 0040-256-403578, email: dana.silaghi@mec.upt.ro Abstract: Because the nitrogen dioxide has noxious effects to human health and also to the environment, the European and the national laws in environmental field impose strict norms to the large polluters. According to these laws, they are obligated to optimize the plants performances in order to reduce the pollution. The case study presented in this paper describes the simulation of the nitrogen dioxide dispersion phenomenon in Timisoara city atmosphere, with the help of analytical-experimental methods. The objective is to establish the influence of micro-plants an also of the two thermal power stations, that make the thermal energy supply of the population, to nitrogen dioxide pollution level, in down town, into a reference point. Keywords: atmospheric pollution, simulation, dispersion. 1. Introduction The nitrogen dioxide has noxious effects to human health and also to the environment. The most noxious action of nitrogen dioxide is his indirectly contribution to the global heating and the greenhouse effect [1]. As a result, the European Union imposed as nitrogen dioxide limit values the guide values of the Health World Organization (OMS). Romania adopted into the national laws these values. The study of the influence that have different pollution sources to the atmospheric pollution and also the modeling of the phenomenon witch accompany the nitrogen dioxide dispersion in its cycle in nature is current and of a particular importance. This fact leads to the development of some series of mathematical models that allow the estimation and study of the main parameters that influence the degree of pollution with nitrogen dioxide and with other pollutants. [2-7] In this paper was studied the influence that different pollution sources have on to the nitrogen dioxide pollution measured in a certain reference point – Mihai Viteazu Boulevard, the residence of Timisoara Environment Protection Agency. The main nitrogen dioxide pollution sources existing in Timişoara municipalities are: two thermal power stations that make the thermal energy supply of the population – Center CET and South CET, the road traffic and micro-plants – in this class are included: apartment micro-plants, the ones in the industrial sector and gas heaters. 2. Experimental The parameters taken into account for the elaboration of this study were: nitrogen dioxide emissions coming from the two thermal power stations (Center CET and South CET), from the micro-plants, the wind speed and direction, the cartesian coordinates of the reference point related to the emission sources, the height of the pollution sources. The experimental data were obtained on the basis of the legal documents supplied by: Distrigaz Nord, Colterm Timişoara, Timişoara Weather Center, and Timişoara Environment Protection Agency. Colterm Timişoara supplied the daily NO x emissions for the months January, April, July, October 2004, for all the boilers and CAFs that exist at Center CET and South CET, according to Romanian legislation [8,9]. The parameters taken into consideration in the calculus algorithm were: gas composition, black oil composition, emission factor for NO x , sulfur retention degree, gas fuel humidity, general data on the boiler, CO 2 and O 2 concentration in the burning gases. Distrigaz Nord supplied the daily consumption values of natural gas in Timişoara for the months January, April, July, October 2004 and gas chromatographic analysis bulletins, made according to STAS 12001–81, for the same period. Based on this data it was calculated the nitrogen dioxide emission coming from the micro-plants of the city according to an algorithm developed based on the literature data. [6] The data received from the Timişoara Weather Center contained the daily values of the weather parameters: wind speed and direction for the same period of the year 2004, in Timişoara municipality. Timişoara Environment Protection Agency supplied the daily values of the total nitrogen dioxide concentration, measured in a certain reference point – Mihai Viteazu. Based on the data received from the abovementioned institutions, the values of NO 2 concentrations in a certain reference point (Mihai Viteazu Boulevard, the residence of